Crimping tool for crimping the terminal sleeve of an electric connector plug



Sept. 18, 1956 PRIOR ART INVENTORS HENRY J. MODREY JOSEPH F. HEALY BY MA 1&

ATTORNEY the terminal sleeve.

United States atet 'CRIMPING TOOL FOR CRIMFTNG THE TERMINAL SLEEVE OF AN ELECTRIC CONNECTOR PLUG Henry J. Modrey, Stamford, and Joseph F. Healy, Westport, ComL, assignors to Interlock Corporation, New York, .N. Y.

Application February 11, 1953, Serial No. 336,218

.1 Claim. ((31. 81-15) The present invention relates to a crimping tool for securing an electrically conductive wire to a Wiring termina-l, more particularly to a crimping tool for securing an electrically conductive wire within the sleeve shaped lug of awiring terminal.

There are known crimping tools in form of pliers the two jaws of which are formed with a comparatively shallow. crimping slot and a nose coacting with the slot. The terminal sleeve to be crimped with the wire inserted therein, is fitted in the slot and the jaws of the pliers are closed whereby "a crimping groove is pressed in the sleeve. As a result ofthe crimping operation, the "sleeveis more or less squeezed out of its original cylindrical shape. v

Such deformation of the receiving sleeve is generally undesirable as it gives the 'wire terminal a squashed 'unsightly appearance; and it is specifically undesirable when the terminal sleeve is intended to b'e passjed through or to project from a round hole or opening in the shell or cover of ane'lec'trical connector, as such hole or opening should forma rather tight fit for'the sleeve coacting therewith. Obviously, a deformed sleeve cannot be passed through a round hole or opening or at least not form a tight fit therewith.

More specifically, any appreciable deformation of the terminal sleeve must be avoided when the terminal sleeve is a part of the plug of a self-locking connector and is required to telescope within the shell or casing of the plug. Such self-locking connectors are described for instance in the prior United States Patent 2,423,250 of one of the applicants herein and in the pending application Ser, No. 173,733 filed July 7, 1950 by one of the applicants herein and now Patent 2,721,981 issued October'25, 1955. The locking and contact mechanism of a connector of this type includes, among other components, aclampin'g rod having on oneend an eccentrically enlarged clamping head and on the other end the terminal sleeve. The rod and its terminal sleeve are slidably guided in an actuating sleeve-which for locking the plug and releasing the same from its socket is telescoped relative to the clampin'g'rod andthe terminal sleeve. A's'will be evident, a' deformation of the terminal sleeve bythe clamping'operationas hereinbefore described, prevents such relative movement and hence the functioning of the connector.

Accordingly, the principal object of the present invention is to provide a noveland improved crimping tool so designed that'a terminal sleeve crimped by means of the said .tool retainsits original. cross-sectional configuration,..at least toan extent sufiicient for all practical ,purposes. In other words, the grooving'of the wall ofthe terminal sleeve. inherent in a crimping operation does not appreciably affect the original cross-sectional outline of As a result, the aforementioned disadvantages of a deformation of the terminal sleeve crimped with. a. crimping tool as hitherto known are eliminated.

A more specific object of the invention is to provide a novel and improved crimping pliers the crimping slot of which has a configuration such that it positively retains the terminal sleeve in its original general shape whenthe nose coacting with the crimping slot is pressed into the sleeve during the crimping operation.

Other and further objects, features and advantages of the invention will be pointed out hereinafter and set forth in the appended claim. v

In the accompanying drawing several now preferred embodiments of the invention are shown by way of illustration and not by way of limitation.

In the drawing:

Fig. l is a fragmentary view' of the jaws of a crimping pliers as hitherto known. I

Fig. 2 is a view partly in section of a plug of a selflocking connector the terminal sleeve of whichi's crimped with the pliers of Fig, 1.

Figs. 3 and 3a are a section taken on line 3--3 of Fig.2 and a view of the terminal sleeve respectively after'the crimping operation. I

Fig. 4 is a fragmentary view of the jaws of a crimping pliers according to the invention.

Fig. 5 is a view similar to Fig. 2 but showing the terminal sleeve of the plug crimped with the pliers 'of'Fig; 4.

Figs. 6 and 6a are a section taken on line 6-'6 er Fig. 5 and a view of the terminal sleeve respectively after the crimping operation.

Fig.7 is an isometric view of a modification of a crimping tool according to the invention.

Referring first to Fig. 1 showing the prior art, the crimping pliers according to this figure comprises tw-o jaws 1'0 and 11 pivotally joined by a rivet 1'2. Jaw 1 0 includes in its .face coacting with the respective face of jaw 11 a comparatively shallow crimping slot'lii. This slot coac'ts with a crimping element in form of a nose .14 extending from jaw 11 and protruding into the crimping slot when the jaws of pliers are closed as is shown. Let it now be assumed that it is desired to crimp a terminal sleeve having a circular cross-section, the diameter of which is larger than the maximum depth of slot 13. The terminal sleeve to be crimped is shown as a component of a plug of a self-locking connector of the type previously referred to, more specifically of the type described in Patent 2,721,981.

According to Fig. 2, the plug comprises an actuating sleeve 15 closed at one end by a wall member having an opening therethrough. An electrically conductive clamping rod 16 is slidably guided within sleeve 15. The-end of the clampingrod protruding from said'wall member is bent back to form a clamping head 17 one-sidedly overhanging sleeve 15. The other end of the rod supports thereon a terminal sleeve 18 within which around wire conductor 19 is secured by the crimping operation. The full outline of the sleeve shows the configuration of the terminal sleeve after the crimping operationand the dotted outline before the crimping operation. This latter outline should be visualized as showing the sleeve in its .rounded shape. A spring 20 within sleeve 5 biases the rod andits clamping-head into the position relativet-o sleeve 15 that is shown in Fig. 2.

A'detailed description of the operation of the plug and its -.coaction with the socket of the connector (not shown) arev not deemed to be essential for an understanding of the invention. It suffices to state that both the locking operation and the release operation involve a telescopic movement of sleeve 15 relative to the rod and, hence,.relative to terminal sleeve 18.

Fig. 3 shows in dotted lines the original round configuration of the terminal sleeve and also the outline-of .the sleeve after-the crimping operation. As will beobserved, sleeve 18 is forced out of its round configuration as the shallowness of crimping slot 13 and the widening of the slot toward its mouth do not confine the sleeve to a circular shape when the pressure of thev crimping nose 14 is applied to the sleeve and produces the crimping groove21 therein.

(full outline) does not permit such relative telescoping movement.

Referring now to Fig. 4 which shows a crimping pliers according to the invention, jaw of this pliers is formed with a crimping slot 25. In contrast to the conventional shallow crimping slot as hereinbefore described, crimping slot 25 is formed with straight side walls and a semicircular bottom portion. The radius of this bottom portion corresponds to the radius of sleeve 18 in its original round shape; the maximum width of the slot corresponds to the diameter of sleeve 18 and the maximum depth of the slot is at least equal to but preferably slightly larger than the diameter of sleeve 18. The crimping nose 14 protruding from jaw 11 is basically similar to the crimping nose 14 but preferably slightly longer as sleeve 18 when in position for crimping is seated deeper in slot 25 than in slot 13. As shown in Fig. 4 the tip of nose 14 is convex toward the base of slot 25 in the direction transverse of the length of the indentation crimped in the sleeve. As shown in Fig. 7 it may also be convexly curved in the longitudinal direction of the indentation crimped in the sleeve. By reason of the aforementioned configuration of slot 25 sleeve 18 is positively retained within its original round outline and the deformation of the sleeve by the crimping groove 21 extends entirely and exclusively toward the center of the sleeve as is clearly shown in Fig. 6. As a result, the aforementioned telescopic motion between sleeves and 18 can be performed with- -out difficulty as can be clearly seen in Fig. 5. Due to the convex curvature of the nose in both, axial and transverse direction, the danger of a cutting of the sleeve metal is avoided and the sleeve metal is pressed strongly against the wire to be secured to the sleeve.

Fig. 7 shows a crimping tool according to the invention which is designed as a hand or bench tool. The crimping -tool comprises an arm 30 and an arm 31 pivoted to arm 30 by means of a pivot 32. The crimping slot of the tool is shown as an elongated channel 33 which may be formed by correspondingly bending or otherwise shaping a plate 34 secured to arm 30 by any suitable means such as screws 35. The cross-sectional outline of channel 33 is such that it satisfies the definitions given in connection with slot 25, that is, the bottom portion of the channel is semi-circular and has a radius corresponding to the radius of terminal sleeve 18 of the plug shown in phantom; the maximum width of the channel corresponds to the diameter of sleeve 18; and the maximum depth of the channel is equal to but preferably larger than the diameter of sleeve 18. Wall portion 34 of plate 34 and part of the plate abutting against arm 30 are formed with a transverse slot 36. This transverse slot is so positioned that when a plug is placed in the cradle formed by the crimping channel in a position in which a collar 37 of the plug engages slot 36, terminal sleeve 18 of the plug is located and positively held in the correct position for crimping.

The crimping element of the tool consists of a cam 40 formed at the end of arm or lever 31 and having a cam surface curved convexly in the axial direction of channel 33. As will be noted, pivot 32 constitutes the fulcrum of the cam. Pivoting of arm 31 in the direction of the arrow causes the respective portion of the cam surface progressively to enter the crimping cradle thereby crimping the terminal sleeve of a plug placed in the cradle. As will be observed, the pivotal movement of cam 40 is in the direction of the longitudinal axis of the cradle. Such cam action produces a strong forward thrust in the direction of the longitudinal axis of the plug. It is, therefore, advantageous to close the portion of the cradle receiving plug sleeve 15 and clamping head 17 by a wall 38 forming a stop for the hook-shaped clamping head and the rod 16 to which sleeve 18 is fastened, thereby avoiding that the terminal sleeve is pushed forwardly relatively to plug sleeve 15 which is located by slot 36.

The two arms 30 and 31 may be manually operated but arm 30 may also be visualized as being attached to a bench or a bracket. For this purpose arm 30 is shown as being provided with holes 41. Arm 30 may be manually operated even though arm 30 is attached to a bench or bracket but it may also be connected to a rod for foot treadle operation. It is provided for this purpose with a hole 42.

While the invention has been described in detail with respect to certain now preferred examples and embodiments of the invention it will be understood by those skilled in the art after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, to cover all such changes and modifications in the appended claim.

What is claimed as new and desired to be secured by Letters Patent, is:

We claim:

A crimping pliers for forming a longitudinal indentation of predetermined length, width and depth in the wall of the cylindrical terminal sleeve of a self-locking electric connector plug of the kind in which the locking action is effected by telescoping the terminal sleeve into a second sleeve of the plug, to secure a wire in the terminal sleeve while substantially maintaining the cylindrical cross-section thereof, the said pliers comprising two jaws hingedly joined for movement between a spread apart position and a closed position, said jaws having each a plane face which faces are in abutment in the closed position of the jaws, one of said jaws including in its face an elongated crimping slot having a configuration such that its maximum width fits the outer diameter of the sleeve to be indented, that its bottom portion is semi-circular and that its maximum depth is at least equal to the outer diameter of the sleeve, and the other jaw having on its face an elongated crimping nose transversely protruding therefrom and extending into the slot in the closed position of the jaws, said nose having a tip curved convexly both in transverse and in longitudinal direction relative to said slot, said convex curvatures facing the bottom of the slot, said nose being situated in said closed jaw position parallel to and equally spaced from the lateral walls of the slot, the width and length of the nose corresponding to the prescribed width and length respectively of the indentation and the distance between the tip of the nose at any point along the entire length thereof and the bottom of the slot being equal to the daimeter of the sleeve less the prescribed depth of the indentation.

References Cited in the file of this patent UNITED STATES PATENTS 954,297 Jackson Apr. 5, 1910 1,326,820 Youdelman Dec. 30, 1919 1,394,719 Evenden et a1 Oct. 25, 1921 1,473,471 Davis Nov. 6, 1923 1,842,678 Kreuzeder Jan. 26, 1932 2,014,062 Braddock Sept. 10, 1935 2,583,625 Bergan I an. 29, 1952 2,590,364 Adas Mar. 25, 1952 

